Prepare the Steak: If you haven't already, slice your partially frozen steak as thinly as you can against the grain. Season the slices with the salt and black pepper and set aside.

Sauté the Vegetables: Heat the olive oil in a large frying pan or skillet over a medium heat. Add the sliced onion and green pepper and cook, stirring occasionally, for 6-8 minutes, until they are soft and the onions are translucent and starting to sweeten. Add the minced garlic and cook for one more minute until fragrant. Remove the vegetables from the pan and set them aside.

Cook the Steak: In the same pan, increase the heat to medium-high. Add the sliced steak in a single layer (you may need to do this in two batches). Cook for 1-2 minutes per side, until just browned. The thin slices will cook very quickly. Don’t overcrowd the pan and don’t overcook the meat, or it will become tough.

Combine the Filling: Return the cooked vegetables to the pan with the steak. Reduce the heat to low. Stir in the Worcestershire sauce and soy sauce, ensuring everything is well-coated. Turn off the heat.

Add the Cheeses: Add the grated mozzarella to the pan and stir through the beef and vegetable mixture until it just begins to melt. This will help bind the filling together.

Assemble the Roll Ups: Lay a tortilla flat. Place one slice of provolone cheese slightly off-centre. Spoon about one-eighth of the beef mixture on top of the cheese. What works best for me is letting the filling cool for just a minute or two; this makes the tortillas much easier to roll without tearing.

Roll Them Tight: Fold in the sides of the tortilla, then roll it up tightly from the bottom, like a burrito. Repeat with the remaining tortillas and filling.

Pan-Fry to Perfection: Melt half the butter in a clean, large frying pan over a medium heat. Carefully place four of the roll ups in the pan, seam-side down. Cook for 2-3 minutes per side, until the tortilla is golden brown, crisp, and the cheese inside is completely melted and gooey. Repeat with the remaining butter and roll ups. Serve immediately.